package core;

import java.io.IOException;

import org.apache.lucene.analysis.standard.StandardAnalyzer;
import org.apache.lucene.document.Document;
import org.apache.lucene.document.Field;
import org.apache.lucene.index.CorruptIndexException;
import org.apache.lucene.index.IndexWriter;
import org.apache.lucene.queryParser.ParseException;
import org.apache.lucene.queryParser.QueryParser;
import org.apache.lucene.search.IndexSearcher;
import org.apache.lucene.search.Query;
import org.apache.lucene.search.ScoreDoc;
import org.apache.lucene.search.TopScoreDocCollector;
import org.apache.lucene.store.Directory;
import org.apache.lucene.store.LockObtainFailedException;
import org.apache.lucene.store.RAMDirectory;
import org.apache.lucene.util.Version;

public class TutorialMain {

	/**
	 * @param args
	 * @throws IOException 
	 * @throws LockObtainFailedException 
	 * @throws CorruptIndexException 
	 * @throws ParseException 
	 */
	@SuppressWarnings("deprecation")
	public static void main(String[] args) throws CorruptIndexException, LockObtainFailedException, IOException, ParseException {
		// 0. Specify the analyzer for tokenizing text.
	    //    The same analyzer should be used for indexing and searching
	    StandardAnalyzer analyzer = new StandardAnalyzer(Version.LUCENE_CURRENT);

	    // 1. create the index
	    Directory index = new RAMDirectory();

	    // the boolean arg in the IndexWriter ctor means to
	    // create a new index, overwriting any existing index
	    IndexWriter w = new IndexWriter(index, analyzer, true, IndexWriter.MaxFieldLength.UNLIMITED);
	    addDoc(w, "Lucene in Action");
	    addDoc(w, "Lucene for Dummies");
	    addDoc(w, "Managing Gigabytes");
	    addDoc(w, "The Art of Computer Science");
	    w.close();

	    // 2. query
	    String querystr = args.length > 0 ? args[0] : "lucene";

	    // the "title" arg specifies the default field to use
	    // when no field is explicitly specified in the query.
	    Query q = new QueryParser(
	    Version.LUCENE_CURRENT, "title", analyzer).parse(querystr);

	    // 3. search
	    int hitsPerPage = 10;
	    IndexSearcher searcher = new IndexSearcher(index, true);
	    TopScoreDocCollector collector = TopScoreDocCollector.create(hitsPerPage, true);
	    searcher.search(q, collector);
	    ScoreDoc[] hits = collector.topDocs().scoreDocs;
	    
	    // 4. display results
	    System.out.println("Found " + hits.length + " hits.");
	    for(int i=0;i<hits.length;++i) {
	      int docId = hits[i].doc;
	      Document d = searcher.doc(docId);
	      System.out.println((i + 1) + ". " + d.get("title"));
	    }

	    // searcher can only be closed when there
	    // is no need to access the documents any more. 
	    searcher.close();
	}

	private static void addDoc(IndexWriter w, String value) throws CorruptIndexException, IOException {
		 Document doc = new Document();
		    doc.add(new Field("title", value, Field.Store.YES, Field.Index.ANALYZED));
		    w.addDocument(doc);		
	}

}
